Releasable clamp for a driving member of a strip-like medium

ABSTRACT

A device for releasably clamping a driving member of a striplike medium in a desired transverse position with respect to a feed direction where the driving member is axially slidable along a transverse shaft. A pivotal clamping member with a friction surface abuttable against the shaft is biased in abutment therewith by a resilient biasing means. Pivotal displacement of the clamping member is opposition to the biasing means serves to free the driving member for axial adjustment along the shaft.

United States Patent Funk [ 1 Sept. 26, 1972 [54] RELEASABLE CLAMP FOR A DRIVING MEMBER OF A STRIP-LIKE MEDIUM [72] Inventor: Joseph W. Funk, Dearborn, Mich.

[73] Assignee: Burroughs Corporation, Detroit,

Mich.

[22] Filed: Jan. 4, 1971 [2i] Appl. No.: 103,729

[52] US. Cl ..226/74, 226/79 [51] Int. Cl. ..G03b 1/30 [58] Field of Search v.226/74, 75, 79, 179; 269/59 [56] References Cited UNITED STATES PATENTS 2,630,90l 3/1953 Johnson ..226/79 2,893,275 7/1959 Lindemann ..269/58 UX Primary Examiner-Richard A. Schacher Attorney-Kenneth L. Miller and Edwin W. Uren [57] ABSTRACT A device for releasably clamping a driving member of a strip-like medium in a desired transverse position with respect to a feed direction where the driving member is axially slidable along a transverse shaft. A pivotal clamping member with a friction surface abuttable against the shaft is biased in abutment therewith by a resilient biasing means. Pivotal displacement of the clamping member is opposition to the biasing means serves to free the driving member for axial adjustment along the shaft.

5 Claims, 4 Drawing Figures PATENTEI] W m FIG.

INVENTOR JOHN W. FUNK AGENT RELEASABLE CLAMP FOR A DRIVING MEMBER OF A STRIP-LIKE MEDIUM BACKGROUND OF THE INVENTION This invention relates generally to apparatus for feeding a strip-like medium such as journal paper past a work station and more particularly concerns releaseable locking means for movable paper strip driving members.

In most apparatus that require the feeding of striplike media past a work station, members for driving the strip must be disposed in predetermined exacting positions with respect to the strip-like media. This is especially true in the case of many high speed printers where marginal perforations in a long strip of paper are engaged by pins of a driven wheel or tractor to move the paper intermittently through a printing station. Usually two pin wheels or tractors are used to engage perforations in opposite margins, thus the width of the paper determines the distance between the two tractors while minute variations in this distance affect the transverse tension on the paper strip. The capability of effecting positional variations of the tractors in a transverse direction with respect to paper feed is highly desirable in order to extend the use of printing or other apparatus to paper of varying widths and to permit adjustment of transverse strip tension to compensate for small width variations due to temperature, humidity and so forth.

Early devices of the prior art accommodated this need by providing a pin wheel or tractor that was axially slidable along a driven shaft extending transversely with respect to the direction of web feed. The pin wheel was then releaseably coupled to the shaft by means of set screws so that adjustment ofthe transverse positions thereof was accomplished by loosening the screws, sliding the pin wheel to a desired position and then tightening the screws. This obviously was a time and labor consuming process. An example of one of several of the more sophisticated approaches may be seen in US. Pat. No. 2,683,599 to Davidson in which a transverse driving shaft for a pin wheel is provided with an axially spaced series of grooves into which a locking means of the paper driving member are releaseably engageable for gross axial adjustment of the paper driving member along the shaft. For fine adjustment a vernier is provided to allow axial displacement of the paper driving member to positions between the discrete slots in the driving shaft.

The complexity of this and other approaches to adjusting the positions of paper feeders is evidence of the need for a simpler solution. Accordingly, it is a primary object of the present invention to provide an uncomplicated and reliable means for releaseably locking an axially slidable driving member to a shaft.

It is also an object of the present invention to permit a fast and facile manual adjustment of the driving member along the shaft.

It is further an object of the present invention to allow for continuous adjustment of the paper driving member to any axial position on the shaft.

In one of its aspects the invention provides two modes for release of the paper driving member, one being associated with the lifting of a tractor cover in preparation for the insertion of a new strip of paper and the other involving the mere depression of a button.

In another of its aspects the present invention frictionally engages a transverse shaft with a vibration dampening material so that the tendency of vibrations inherent in the associated apparatus to move the tractor out of alignment with the perforated margins is abated.

SUMMARY OF THE INVENTION In accordance with the invention, a paper driving member is axially slidable upon a shaft transversely with respect to the direction of paper feed so that the driving member may be laterally positioned to engage marginal perforations in paper strips of varying widths and to adjust transverse strip tension. A clamping member is pivotally mounted on the paper driving member such that the pivotal motion thereof traverses a plane substantially perpendicular with respect to the axis of the shaft. The clamping member has a friction surface that is abuttable with the shaft when the clamping member is pivoted in a predetermined direction. Firm abutment of the clamping member with the shaft axially locks the paper driving member thereto. To firmly abut the clamping member with the shaft a resilient biasing means is provided that yieldably forces the clamping member in a predetermined pivotal direction so that the friction surface of the clamping member is in firm abutment with the shaft. The clamping member is then pivotally displaceable in opposition to the resilient biasing means for freeing the driving member from the shaft to permit transverse adjustment.

BRIEF DESCRIPTION OF THE DRAWINGS In order to facilitate a more complete understanding of the invention, a preferred embodiment thereof will hereinafter be described with reference to the drawings in which:

FIG. 1 is a top plan view illustrating a paper driving apparatus in which the present invention has been incorporated;

FIG. 2 is a side view taken along lines 2-2 of FIG. 1;

FIG. 3 is a fragmentary view similar to FIG. 2 showing the clamping member pivoted to a released position; and

FIG. 4 is an end view taken in the direction of arrow 4 in FIG. 3.

DETAILED DESCRIPTION OF THE INVENTION Turning now to the figures wherein like reference characters designate identical elements in each of the drawings and particularly to FIG. I, there is shown two paper driving members or tractors l0 engaged with marginal perforations 12 in a paper strip 14. Pins 16 of each tractor engage corresponding perforations 12 in the paper strip 14 and are carried in an endless loop by a tractor belt 18 (FIG. 4). Two shafts extend transversely through openings in the paper driving tractors 10; one being a splined shaft 20 that serves to drive the tractor belts l8 and the other being a smooth shaft 22 that supports and transversely guides the slidable tractors 10. Both shafts 20 and 22 are bearingly journaled in opposing side plates 24. The splined shaft 20 is coupled exteriorly of the leftmost side plate 24 to a driving means 26 for rotation in a predetermined direction and for predetermined durations to establish a printing format. Both paper driving tractors 10 are axially slidable along the shafts 20 and 22 in order to adjust the pin positions with the marginal perforations 12 in paper strips of various widths. Once the paper driving tractors 10 have been axially slid to desired positions on the shafts 20 and 22 in accordance with the paper width, the present invention provides a means to restrain further axial displacement so that during a paper driving operation the tractors will remain in their preestablished positions. When new paper is threaded on the apparatus or when the transverse tension on the paper must be altered the axial restraint imposed on the driving members by the invention is readily deactuatable.

This is accomplished in the present instance by biasing a friction surface 28 of a pivotal clamping member 30 into firm abutment with the smooth shaft 22, as best illustrated in FIGS. 2 and 4, the firmly abutting friction surface serving to restrict axial movement of its as sociated paper driving tractor 10. The clamping member 30 of each tractor is mounted on a clamping member support plate 32 that is firmly fastened to the paper driving tractor l and, as such, may be considered an integral part thereof. The friction surface 28 of the clamping member 30 is formed in substantially the same shape as the portion of the smooth shaft 22 against which it abuts, thus enlarging the effective frictional area of contact. The clamping member 30 is pivoted about a pivot shaft or pin 34 extending from the support plate 32, such that the friction surface 28 may be pivotally displaced from the smooth shaft 22.

The clamping member 30 is biased pivotally clockwise, as shown, to carry the friction surface 28 thereof into firm abutment with the smooth shaft 22. Resilient biasing means in the form of a helical compression spring 36 extends downwardly from the under surface 38 of the clamping member 30 into contact with a parallel ledge 40 of the clamping member support plate 32. The compressive force transmitted by the compression spring 36 from the ledge 40 to the clamping member 30 provides an abutting force between the smooth shaft 22 and the friction surface 28 of such magnitude that the associated paper driving tractor is maintained axially rigid during paper driving opera tions. It has been found that a compressive force sufficient for locking the tractor 10 to the shaft 22 will not prevent a facile manual depression of the clamping member 30 in opposition thereto, such depression being effective to remove the friction surface 28 from abutment with the smooth shaft 22 and to allow axial adjustment of the paper driving tractor 10.

A raised portion 42 of each clamping member 30 provides a button-like surface which may be conveniently engaged by a finger for releasing the clamp ing member from the smooth shaft 22v The raised por tion 42 also provides an abutting surface for a clamp engaging extension 44 of a hinged tractor cover 46 so that when the tractor cover 46 is pivoted upwardly, as illustrated in FIGS. 3 and 4, in preparation for the threading of a new paper strip, the clamping member 30 is thereby released and convenient axial adjustment of the paper driving tractors 10 is accordingly permitted. When pivoted downwardly, the hinged tractor covers 46 serve to maintain their corresponding sides of the paper strip 14 in engagement with the pins 16 of the driving tractors 10. By pivoting a tractor cover 46 upwardly, as shown in FIG. 4, the pins 16 are exposed so that a new paper strip may be threaded onto the tractor belt 18.

Each clamping member 30 is guided in its pivotal motion by a guide pin 48 extending from the face of its clamping member support plate 32. A slot 50 in the clamping member 30 rides on the pin 48 during pivotal displacement of the clamping member. Ends of the slot 50 establish limits to the clockwise and counterclockwise pivoting motion of the clamping member 30, the upper surface 52 thereof establishing the downward or counterclockwise limit for the clamping members pivotal movement, thereby preventing over compression of the helical compression spring 36.

In operation, for example, when an operator desires to change paper strips, the hinged tractor covers 46 of both paper driving tractors 10 are raised, thus releasing the friction surfaces 28 of the clamping members 30 from firm abutment with the smooth shaft 22. Both paper driving members 10 are then free to slide axially along the shafts 20 and 22 to accommodate the width of the new paper strip. The position of one of the sides of the new paper strip may be established by sliding the paper driving tractor 10 corresponding thereto to the desired position, then threading the perforated margin thereof onto the associated tractor belt 18. The cor responding hinged tractor cover 46 is then closed to thereby lock that paper driving tractor 10 in the desired transverse position. The other paper driving tractor 10 may then be moved so that its corresponding tractor belt 18 is aligned with the perforations 12 on the op posite side of the paper strip. After threading these perforations onto the belt 18 of the latter tractor, the corresponding hinged tractor cover 46 is closed to thereby permit the clamping member 30 thereof to be biased into its locking position.

The frictional surface 28 of each clamping member 30 is preferably the surface ofa pad 53 that is bonded to an indented surface of the clamping member, the pad being composed of a relatively soft material that has a high coefficient of friction with the material composing the smooth shaft 22. Assuming the shaft 22 is metallic, a composition of neoprene has proven to be a desirable substance for the friction surface 28. in addition to its advantageous frictional properities, neoprene is also effective to dampen vibrations inherent in the associated paper driving apparatus, thus abating the tendency of such vibrations to shimmy the paper driving tractors 10 out of alignment with the marginal perforations 12 of the paper.

While the invention has been described in conjunction with a specific embodiment, it is evident that many modifications and alternatives not truly departing from the inventive concept residing therein will be apparent to those skilled in the art in light of the foregoing description. Accordingly, it is intended to embrace within the appended claims all such modifications and alternatives that reside within the inventive concept disclosed herein.

What is claimed is:

l. in combination with apparatus for feeding a striplike medium, said apparatus having a strip driving member axially slidabie upon a shaft disposed transversely with respect to the direction of feed, a device for releaseably clamping said strip driving member to said shaft against such slidable movement, said device comprising:

a supporting plate fixed to said strip driving member,

a hinged cover guide mounted on said supporting plate in cooperating relationship with said striplike medium,

a clamping member pivotally mounted on said supporting plate for pivotal motion in a plane substantially perpendicular with respect to the axis of said shaft, said clamping member having a friction surface abuttable with said shaft for frictionally restraining the axial movement of said driving member along said shaft, and having also a guideway engaged by a guide pin fixed to said supporting plate for guiding the pivotal displacement of said clamping member and for angularly limiting such motion, and

means for resiliently biasing said clamping member pivotally into firm abutment with said shaft, whereby pivotal displacement of said clamping member in opposition to said resilient biasing means frees said driving member for transverse adjustment to any axial position on said shaft.

2. A device as defined by claim 1, wherein said biasing means is a helical compression spring cooperably disposed between a horizontal surface of said pivotal clamping member and a horizontal extending ledge formed in said supporting plate.

3. A device as defined by claim 1, wherein said friction surface is a pad bonded to said clamping member, said pad being composed of a resilient material having a relatively high coefficient of friction with the material of said shaft.

4. A device as defined by claim 3, wherein said pad is composed of neoprene.

5. A device as defined by claim 1, wherein said clamping member has a raised portion disposed apart from the pivot point on the opposite side of the shaft therefrom, and wherein said hinged cover guide comprises an angularly disposed clamp engaging extension cooperable with said raised portion of said clamping member whereby the application of a manual force to said raised portion or the raising of said hinged cover guide is effective for applying a pivoting force to said clamping member in opposition to said biasing means.

It I! i i UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No.

Dated September 26, 1972 Inventor(s) John W. Funk It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Inventor 5 name should read -John W. Funlv- Abstract Section, line 8, change "is opposition" to in opposition-- Signed and sealed this 1st day of May 1973.

(SEAL) fittest:

EDEIARD M. FLETCHER, JR

R ROBERT GOTTSCHALK ."Lttesting Officer Commissioner of Patents 

1. In combination with apparatus for feeding a strip-like medium, said apparatus having a strip driving member axially slidable upon a shaft disposed transversely with respect to the direction of feed, a device for releaseably clamping said strip driving member to said shaft against such slidable movement, said device comprising: a supporting plate fixed to said strip driving member, a hinged cover guide mounted on said supporting plate in cooperating relationship with said strip-like medium, a clamping member pivotally mounted on said supporting plate for pivotal motion in a plane substantially perpendicular with respect to the axis of said shaft, said clamping member having a friction surface abuttable with said shaft for frictionally restraining the axial movement of said driving member along said shaft, and having also a guideway engaged by a guide pin fixed to said supporting plate for guiding the pivotal displacement of said clamping member and for angularly limiting such motion, and means for resiliently biasing said clamping member pivotally into firm abutment with said shaft, whereby pivotal displacement of said clamping member in opposition to said resilient biasing means frees said driving member for transverse adjustment to any axial position on said shaft.
 2. A device as defined by claim 1, wherein said biasing means is a helical compression spring cooperably disposed between a horizontal surface of said pivotal clamping member and a horizontal extending ledge formed in said supporting plate.
 3. A device as defined by claim 1, wherein said friction surface is a pad bonded to said clamping member, said pad being composed of a resilient material having a relatively high coefficient of friction with the material of said shaft.
 4. A device as defined by claim 3, wherein said pad is composed of neoprene.
 5. A device as defined by claim 1, wherein said clamping member has a raised portion disposed apart from the pivot point on the opposite side of the shaft therefrom, and wherein said hinged cover guide comprises an angularly disposed clamp engaging extension cooperable with said raised portion of said clamping member whereby the application of a manual force to said raised portiOn or the raising of said hinged cover guide is effective for applying a pivoting force to said clamping member in opposition to said biasing means. 